You're right, they're not comparable. The technical competency required for engineering exceeds those other fields. I've known so many engineers who've quit and gone into less time consuming areas like law with the secondary benefit of making considerably more.

Whatever, but the disparity in the educational requirements to become a professional engineer compared to MDs and attorneys is great, and that has been and will be reflected in the compensation earned in each field.

Engineering is much more comparable to architecture and CPA work.

And there are plenty of attorneys and doctors and CPAs and others who’d be surprised to learn they work so much less than engineers (because it isn’t true).